Science and technology

Laser-emitting cells

A healthy glow

WHEN the laser was invented in 1960, it was famously described as “a solution in search of a problem”. Technophiles were impressed with the achievement of making millions of photons march in lockstep, but unable to see any real-world uses for it.

Fifty years later, lasers are a staple in everything from astronomy, surgery and DVD players to cutting sheet metal. Now a group of scientists led by Seok-Hyun Yun at Harvard Medical School have upped the ante on technically-neat but not-obviously-useful research, and created a laser from a biological cell (full details available from Nature Photonics).

A working laser requires both a lasing medium—which amplifies externally-supplied light—and an optical cavity, which bounces the light back and forth through the medium until the desired power is achieved. Existing lasers use media ranging from crystals doped with rare-earth elements to specific mixtures of gas and even certain sorts of semiconductors. Dr Yun plumped instead for a chemical called Green Flourescent Protein (GFP), the substance responsible for making certain species of jellyfish glow in the dark. The chemical is well-known to biologists, who use its flourescent properties to keep track of particular proteins and gene sequences.

Dr Yun's team genetically engineered a human embryonic kidney cell to produce GFP, then placed it between two tiny mirrors to form a miniscule optical cavity 0.02mm across. When they shone pulses of light at the cell, it duly produced a “beautiful green” laser beam detectable with the naked eye.

All very impressive. And there may even be practical applications. Laser cells, they say solemnly, could have important uses in medicine. Doctors already deploy more traditional lasers to remove tattoos, correct short-sightedness, cut tissue or whiten teeth. For his next trick, Dr Yun plans to integrate the optical cavity into the cell itself, removing the need for any external equipment besides a light source. How much easier such treatments would be, theorises Dr Yun, if the lasers could be generated internally, by a patient's own cells.

Perhaps. Babbage is no expert on the medical applications of lasers. But it is, shall we say, not intuitively obvious that genetically engineering bits of a human body to express GFP, equipping the cells with optical cavities and then pumping them to produce a laser beam will ever be cheaper or easier than simply buying a traditional, off-the-shelf medical laser from a factory in China. Cynics might see the team's ideas as a particularly good example of the research scientist's art of inventing speculative applications to justify his work to funding bodies, with their insistance that basic science ought, in principle, to be translatable into something practical.

Of course, Babbage would love to be proved wrong. And the achievement does score well in the jaw-dropping department. So much so, in fact, that the researchers might have been better advised to fall back on that traditional justification invoked by scientists who truly cannot think of immediate applications for their work (particularly popular among proponents of human spaceflight, for instance). This is to appeal to the ‘inspiring' qualities of the work, and argue that it will leave schoolchildren gobsmacked and infused with a passion for science. The idea of generating laser beams from one's own body seems to fit the bill.

1. equip microorganisms to produce laser and program them to die within 20 minutes of being created, then insert these microbes into human body to zap cancerous cells. certainly far far cheaper (as far as operational costs go) and less painful than all the current treatments.

2. similar treatment for various stones in gall-bladder/kidney/etc.

3. a totally new way to manufacture an entire range of laser enabled gadgets. program the microbes to build micro-laser 'cells' in any array (such as a holographic display) and then die. as for costs, it may or may not be cheaper than current semiconductor crystal growth based processes. but why it is not worth a try ?

4. freezing/hibernating laser enabled microbes in a spacecraft or probe to be activated at a predetermined time.

it is quite dismaying to see babbage adopting a technophobe reactionary language. not true to your job dear, eh ?

Surely the second half of this article contradicts the first half entirely. You state that lasers had no imitate use, in the 60s, and were ridiculed at the time, but have now become a ubiquitous and necessary part of every day life. You seem to then dismiss such a fate for biological lasers. As with all pure research, biological lasers might seem pointless now, only to become essential tomorrow: this, not inspiring school children, has always been the strongest argument for pure research in the first place.

What other commenters are describing as the "sneering tone" exactly matches my own experience of how science & its funding really work.

This research is being conducted because it is effing AWESOME. Tragically, however, the ultimate sources of funding are not scientists; and so many non-scientists labour under the misapprehension that awesomeness is not in itself sufficient reason for putting millions of dollars into research.

This strikes me as a scientific discovery that falls squarely into the "Mad Scientist" category. Most of the time, the whacky and disturbing antics of the Mad Scientist simply illustrate the outer boundaries beyond which mankind should never tread, but every once in a while the Mad Scientist stumbles across something useful. I'm not sure whether this particular discovery will become anything useful, but it certainly is whacky and slightly disturbing.

Although GFP is wonderful at making a nice visible wavelength fluorescence, it should be kept in mind that cells naturally contain a number of entities that also fluoresce (if not in the visible spectrum), and are thus potential sources to make cells into lasers using only endogenous components.

Since I don't know much about lasers, I don't know how useful that is if you need to sequester the cell in .02mm. However, an immediate use might be to improve fluorescence activated cell sorting, and important research tool.

"...as a particularly good example of the research scientist's art of inventing speculative applications to justify his work to funding bodies, with their insistance that basic science ought, in principle, to be translatable into something practical."

I always find this sort of attitude to be quite astounding. That viewpoint presupposes an awful lot: primarily that there is some sort of scientific roadmap that guarantees some sort of predetermined outcome. Basic research is called "basic" because we haven't the foggiest notion where it might ultimately lead. The core tenet of science is that we, in fact, have really no idea how reality works. We have a number of fairly functional working theories that describe some behaviours. In the end however the best we can hope to do is some random, trial-and-error experimentation. Through brute intellect and unflagging determination, we manage to claw back the veils of ignorance piece by piece, but in the process, we need to conduct a lot of science that perhaps ultimately leads to no commercial applications (in the eyes of cynics invents nothing more than more funding justifications). Sometimes it means making monkeys snort cocaine. Sometimes its making living tissue shoot lasers. Nobody knows where a line of inquiry will ultimately lead.

I guess in the far future this might be useful for removing tumors internally inside the body without invasive surgery or foreign elements in the body. However getting to that level of technology from here will be hard.